The present invention relates to a database server capable of relocating data distributed between a plurality of processors.
In a distributed database system constituted by a plurality of CPUs (Central Processing Units) having a storage device, data must be relocated when additional CPUs are provided to accommodate an increase in the amount of data to be processed. In the related art, the relocation of data in such a system has normally resulted in significant burdens on the operation of the same such as a need for stopping the system.
As a solution to the problem, for example, JP-A-9-29300 has disclosed a technique for storing data in a newly provided storage area instead of relocating the data when additional CPUs are provided. However, according to the technique disclosed in the publication, at the time of data retrieval, all CPUs retrieve storage devices provided in themselves. The technique is therefore not so preferable in terms of retrieval efficiency. There are demands for a method which allows relocation of data to be carried out efficiently with retrieval efficiency kept high.